1. Field of the Invention
The present invention relates to an electronic component package including an electronic component such as a surface acoustic wave device or the like covered by a molding resin.
2. Background Art
Surface acoustic wave device (hereafter referred to as “SAW device”) 1, an example of electronic components, includes component-substrate (hereafter referred to as “substrate”) 2, interdigital transducer (hereafter referred to as “IDT”) electrode 3 disposed on substrate 2, and component-cover (hereafter referred to as “cover”) 4 covering substrate 2 as shown in FIG. 12. Cavity 5 is formed hermetically between IDT electrode 3 and cover 4 to keep an oscillation space for the surface acoustic waves. SAW devices 1 are formed on wafer-like substrate 2 in an aggregate of SAW devices 1, and are cut and separated into individual pieces by using rotary blade 6. Such a technology of forming the aggregate of electronic components before dicing it into pieces to produce individual electronic components is disclosed in Japanese Patent Publication of Unexamined Applications No. JP2005-45319 and No. JP2005-243702, for example.
However, when SAW device 1 mounted on mounting board 8 via external electrode 7 is molded with a cover 4 side down as shown in FIG. 13, heating sometimes causes damage on SAW device 1. The heat influences could happen in heating processes such as molding or subsequent heat cycles.
This is due to chipping of substrate 2 caused in dicing SAW device 1 by using rotary blade 6. When SAW device 1 with such chipped portions is processed for molding, molding resin 9 will penetrate into the chipped portions. Since molding resin 9 has a lower coefficient of linear expansion than substrate 2, substrate 2 contracts greater than molding resin 9 when molding resin 9 is cooled down. Consequently, cracks will start from the chipped portions on substrate 2.